Co-treatment with quercetin and 1,2,3,4,6-penta-O-galloyl-β-D-glucose causes cell cycle arrest and apoptosis in human breast cancer MDA-MB-231 and AU565 cells.

Breast cancer is the most universal cancer in women, but the medications for breast cancer usually cause serious side effects and offer no effective treatment for triple-negative breast cancer. Here, we investigated the growth inhibitory effects of gallic acid (GA), (-)-epigallocatechin gallate (EGCG), or 1,2,3,4,6-penta-O-galloyl-β-D-glucose (5GG) combined with quercetin (Que) on breast cancer cells. In this study, we tested the combined effects of these compounds on estrogen receptor (ER)/human epidermal growth factor 2 (Her2)-negative (MDA-MB-231), ER-positive/Her2-negative (BT483), and ER-negative/Her2-positive (AU565) breast cancer cells.